babydoc4usmle
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29 y.o. female with a history of irregular menses becomes amenorrheic.
she had no problem conceiving her first child at the age of 23, but she has been trying unsuccessfully to become pregnant in the past two years.
she also notes a weight gain of about 3 kg, increasing fatigue, puffy face and marked cold intolerance. CBC reveals Hb=11.1 and MCV=90.
physical reveals a moderate enlargement of the thyroid.
which following profiles would most likely be seen in this woman:
A. low T3, low T4, high TSH
B. low T3, low T4, low TSH
C. low T3, high T4, low TSH
D. high T3, low T4, low TSH
E. high T3, high T, low TSH
can't wait your explanation
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| me007
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secondary hypothyroidism - B
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| babydoc4usmle
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can you please explain
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| me007
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with all that story with first pregnancy- irregular menses, etc
it just looks like she has problem with pituitary/hypothalamus
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| babydoc4usmle
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same reasoning i applied...
guess what? according to KQB - it is PRIMARY hypothyroidism (choice A) due to Hashimoto thyroiditis.
now comes a Q: why there is a history of amenorrhea?
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| me007
Forum Guru
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it might be just statistics - they want you to know that MCC of hypothyroidism is Hashimoto's thyroiditis.
amenorrhea - secondary.. how else could it be explained?
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| babydoc4usmle
Forum Guru
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in Hashimoto there is a period ofHYOERthyroidism before it gets HYPO... and amenorrhea leads to secondary hypothyroidism
i think they have to revise questions, it is so unfare to try to pack so much information into the head and at the end be convinced tha you know NOTHING....
very depressing
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| Ancylostoma
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I dont know why there is amennorhea, but kaplan clearly mentions that there are anovulatory cycles as a symptom of hypothyroidism. Lol saying that I probably would have thought it was sheehans too ...!!
Edited by Ancylostoma on 01/19/07 - 08:08 PM
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| Palaniappan
Forum Senior
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Hey guys..
Hypothyroidism can increase prolactin secretion leading to amenorrhoea.....I am not sure why it causes..But,this has been mentioned in USMLE World
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| Luckyall
Forum Guru
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Absolutelly, agree with Palaniappan, it is mentioned in one of Kapl Qs... i wrot it down in the book myself.... a great extent hypothyr. ---> increases Prolactin secretion !!!
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| kudo
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why not B?
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| Ancylostoma
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I think because you have an enlarged thyroid, I wouldnt think that the thyroid would enlarge if there was a decrease in TSH.
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| candy1208
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She's been have the problem for 2yrs, should have hypotrophy of thyroid now instead of hypertrophy if it's really Hashimoto's thyroiditis. In terms of prolactin, the prolactin is produced in pituitary, thus secondary hypothyroid can decrease prolactin. Primary hypothyroid can increase prolactin. Thus, I will go with B
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| Ancylostoma
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lol I guess you didnt take time to read the responses, the answer was A
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| new_n_lost
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Guys they have given the most common things which occur in Hashimoto's most of us got consfused of her being normal when the pt was 23 i.e had a baby then she becomes amenorrheic. The classic symptom of Hashimoto's is the late onset n often with transient Hyperthyroid activity which makes it further more difficult to recognize. The 2 points which were really indicative of Hashimoto's were the marginal increase in weight n the menstrual history coupled with palpable thyroid. Increased prolactin secondary to increased thyrotropin-releasing hormone (TRH) leads to decreased LH, FSH and decreased response to GnRH. The result is anovulatory cycles with menstrual irregularities.
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| Ancylostoma
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How does TRH increase prolactin secretion, I was looking for the answer but kept on coming up with, the reason is not know for the mestrual irregularities or they just wouldnt mention why. It might be a dumb question.
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| me007
Forum Guru
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TRH increases prolactin secretion
(hypothalamic control by dopamine - ihibits and TRH- increases prolactin secretion)
prolactin inhibits ovulation by decreasing synthesis and release of GnRH.
In Hashimoto - what happens to TRH?
Decr T4 ->incr TSH -> decr TRH -> decr prolactin ->? ovulation is not inhibited ?
can't get it.
But i found a few qs with same statement - amenorrhea in hypothyroidism
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| Ancylostoma
Forum Guru
Topics: 42
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decreased t4 would lead to increased TSH and TRH. T4 provides feedback to both(converted to t3 in glands). I just didnt know that trh increases prolactin secretion Nice to know .
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